Guest post from Robert E. Harbaugh, MD, FAANS, FACS
AANS Past President
President, Society of Neurological Surgeons
Director, Institute of the Neurosciences
Distinguished Professor and Chair, Department of Neurosurgery
Professor, Department of Engineering Science & Mechanics
The Pennsylvania State University
Milton S. Hershey Medical Center
There seems to be an insatiable public interest in the potential risks of concussions. Because athletes participating in contact sports are exposed to the risk of repeated blows to the head, there is a legitimate concern about their risk of developing delayed neurological dysfunction — such as chronic traumatic encephalopathy (CTE) or other neurodegenerative diseases — because of this trauma. Unfortunately, instead of a measured and reasonable analysis of the relative risks and benefits of participating in contact sports, the media have engaged in a feeding frenzy that has produced the perception of sports-related concussion as a “crisis” affecting American youth. This perception is inaccurate and potentially dangerous.
While it is true that the annual number of reported sports-related concussions has increased, this is largely because:
- The bar for diagnosing a concussion has been lowered; and
- Awareness has dramatically increased.
Previously, the definition of a concussion used to require a loss of consciousness, but now requires only a change in neurological function after a blow to the head. Most of the concussions reported today would not have met the criteria for concussion in the past. It is, therefore, impossible to say if the number of concussive and sub-concussive blows that occur in athletic activities has increased, decreased or stayed the same. What is clear, however, is that there is much greater awareness among coaches, trainers, parents and players about the potential risk of sub-concussive and concussive injury today than there was in the recent past. These episodes are also treated very differently now. Regarding the sport I know best, American football, these include:
- More stringent return to play rules;
- New recommendations for limiting contact in practice;
- Rule changes that reduce the risk of concussion during game play; and
- Improved helmet technology.
Athletics have changed, and today’s athletes are bigger, stronger and faster. Nevertheless, despite these and other changes, sports-related concussions have not previously been (and there is no reason to consider them today) a crisis.
Creating a crisis atmosphere is good for readership, viewership, grantsmanship and fundraising, but it is not conducive to a dispassionate evaluation of the data. I believe that the presently available epidemiological data do not support the existence of a concussion crisis but are very clear regarding another health crisis affecting our children.
A long-term study from the Mayo Clinic1 that assessed whether or not high school football players were at increased risk of neurodegenerative disease deserves more media attention. In this study, students who played football between the years 1946-1956 were compared to their classmates who participated in the band, glee club or choir. Both groups were followed for decades to see if the football players were more likely to develop neurodegenerative disease later in life. This study, published in 2012, did not show a correlation between contact sports and neurodegenerative disease. There was no significant difference between these two groups in:
- Dementias (which would include CTE);
- Parkinson’s disease; or
- Amyotrophic lateral sclerosis.
In other words, with respect to neurodegenerative diseases, playing clarinet was as dangerous (or safe) as playing linebacker.
A second study published in 2012, compared long-term health outcomes of thousands of former National Football League (NFL) players to age and race matched controls in the general population.2 The NFL cohort demonstrated a decreased overall mortality rate. They were also less likely to commit suicide than the controls. If playing in the NFL reliably results in CTE and CTE manifests itself by, among other things, players who take their own lives, we have some explaining to do. Why are these data rarely, if ever, discussed in the press?
Conversely, only those parts of this study that fit the prevailing narrative — that is, playing football results in delayed neurological dysfunction — received much press. The take home message from the data could have been, “NFL players lived longer and committed suicide less often than controls.” Instead, the focus was that there is “a nearly threefold rate of neurodegenerative disease related deaths for the NFL players.” You had to read the article pretty carefully to determine that there were 17 total deaths from neurodegenerative in this cohort of almost 3,500 former players (<0.5 percent) or that neurodegenerative disease was the cause of death in only about five percent of the 334 deceased players. Had the headlines read, “Former NFL Players have five percent risk of dying from neurodegenerative disease,” the response would likely have been different than the response to the headlines that state that, “CTE has been found in the brains of 90 of 94 NFL players and 45 out of 55 college players whose brains were examined.”
These types of headlines leave the impression that almost all athletes who play college or professional football will develop CTE. They don’t mention that selected samples like this tell us very little about the incidence of CTE in football players. If the brains were donated because the former players had symptoms suggestive of CTE, it is not surprising that a high incidence of CTE would be found. This tells you nothing about the thousands of players who do not have such symptoms. In addition, it is becoming increasingly clear that one of the histological hallmarks of CTE — the deposition of tau proteins in the brain — frequently occurs (as demonstrated by a recent study) as part of the normal aging process in patients without cognitive symptoms.3
I worry that the perceived risk of delayed neurodegenerative disease will have a significant negative impact on youth participation in sports. Although the presently available data have not established a causal relationship between sub-concussive repetitive head trauma and delayed neurodegenerative disease, the prevailing narrative in the media makes it seem like letting children play contact sports is a terribly dangerous thing to do, and parents are becoming increasingly concerned about letting their kids participate. This is a tragedy because we do have a real youth health crisis in the United States — childhood obesity. Limiting opportunities for vigorous exercise will only make this real crisis worse.
Childhood obesity rates in the U.S. have tripled in the past 30 years, and it is now estimated that more than one in three children in the United States are overweight or obese. This is a real crisis as obesity leads to health problems like diabetes, heart disease, high blood pressure, high cholesterol, asthma and sleep apnea. It is also evident that obese children and teenagers are more likely to become obese adults. The crisis of childhood obesity is real and of considerable magnitude. Every time we convince a parent or child that it is too dangerous to play football or soccer or lacrosse, or to get on a bicycle without dressing up like Sir Lancelot, we risk making the real crisis worse.
Surely, understanding concussions is important, while greater awareness of prevention and treatment is critical. However, the epidemic of childhood obesity demands that we also ensure that our youth are encouraged to be physically active and to develop a lifelong commitment to health and wellness.
1. Savica R, Parisi JE, Wold LE, Josephs KA, Ahlskog JE. High school football and risk of neurodegeneration: a community-based study. Mayo Clinic proceedings. Apr 2012;87(4):335-340.
2. Lehman EJ, Hein MJ, Baron SL, Gersic CM. Neurodegenerative causes of death among retired National Football League players. Neurology. Nov 6, 2012; 79(19):1970-1974.
3. Elobeid A, Libard S, Leino M, Popova SN, Alafuzoff I. Altered proteins in the aging brain. J Neuropathol Exp. Neurol. 2016 Mar 15. (Epub ahead of print)